Glass strand is typically formed by attenuating glass filaments from bushing tips in a bushing, applying a binder and/or size to the drawn filaments, collecting filaments into a unified glass strand and winding the strand around a mandrel on a winder. This forms a generally barrel-shaped package of wound glass strand. Typically, these packages contain about 20 to 30 pounds (9.1 to 13.6 kilograms) and do not normally exceed about 110 pounds (49.9 kilograms).
It is known to form containerized packages of glass strand having 300 pounds (136.1 kilograms) or more glass strand therein as, for example, in U.S. Pat. Nos. 3,120,689 and 3,430,312.
It is also known to attenuate glass strand between a pair of belts as illustrated in U.S. Pat. No. 3,293,013 or U.S. Pat. No. 3,887,970. With the belt attenuators shown in the prior art two problems arise due to the nature of the belts. Because the belts are smooth, when attempting to pull glass strand from a large, high tension bushing, the belt attenuators tend to slip and will not give sufficient attenuative force to satisfactorily pull the glass strand and the associated filaments out of the bushing and form the filaments. Also, because of the smooth surface of the belts, the pulled glass strand sometimes will wrap around one of the belts instead of maintaining its trajectory towards the container, requiring sharp turns in the belts at their separation point.
It is desirable, therefore, to produce a belt attenuator which is free of the problems associated with the prior art belt attenuators for forming containerized packages of glass strand.